java 63. Unique Paths II（＃）。java

Posted 2021-05-08

public class Solution {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        if (obstacleGrid == null || obstacleGrid.length < 1 || obstacleGrid[0].length < 1) return 0;
        int m = obstacleGrid.length;
        int n = obstacleGrid[0].length;
        int[][] dp = new int[m][n];
        int ii = 0;
        while (ii < m && obstacleGrid[ii][0] == 0) {
            dp[ii++][0] = 1;
        }
        int jj = 0;
        while (jj < n && obstacleGrid[0][jj] == 0) {
            dp[0][jj++] = 1;
        }
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                if (obstacleGrid[i][j] != 1) {
                    dp[i][j] =  (obstacleGrid[i - 1][j] == 1 ? 0 : dp[i - 1][j]) +  
                                (obstacleGrid[i][j - 1] == 1 ? 0 : dp[i][j - 1]);             
                }
            }
        }
        return dp[m-1][n-1];
    }
}